I went to confession and confessed my sins openly. Then the priest asked me why I committed a particular sin. What motivated me? I wasn’t completely honest about why I did it because I thought I would come off as not feeling sorry for my sin. Was my unwillingness to say why I committed a sin a mortal sin in itself?

Obviously it is on your conscience so the best course of action is to go back to confession and discuss it with the priest. Until then lay your concerns at the feet of of Christ and ask him to take away the burden until you can resolve it and His mercy will find you.

I went to confession and confessed my sins openly. Then the priest asked me why I committed a particular sin. What motivated me? I wasn’t completely honest about why I did it because I thought I would come off as not feeling sorry for my sin. Was my unwillingness to say why I committed a sin a mortal sin in itself?

I would say no, because you’re here asking whether or not it was a mortal sin… However, it would be best to talk to your confessor when in doubt. I suggest going to one confessor if you don’t already. Make an appointment with him, pray to Jesus, and allow yourself to relax in the meantime.

By you asking if it is a mortal you therefore do not know and you have not fulfilled those requirements. Thus at most it could be venial. But if you stated all of your sins that is what is important. As long as you stated the sins and didnt withhold anything intentionally then you should have been validly absolved. The priest may ask questions to get “read” on you to make sure you are sorry for your sins. But I myself am very scrupulous so I can sympathize with your worry. Just go to confession again when you can. But as for it being mortal I would say no its not.

By you asking if it is a mortal you therefore do not know and you have not fulfilled those requirements. Thus at most it could be venial. But if you stated all of your sins that is what is important. As long as you stated the sins and didnt withhold anything intentionally then you should have been validly absolved. The priest may ask questions to get “read” on you to make sure you are sorry for your sins. But I myself am very scrupulous so I can sympathize with your worry. Just go to confession again when you can. But as for it being mortal I would say no its not.

Sorry, but this is incorrect. A person isn’t afforded a “free sin pass” just by saying “I wonder if this is a mortal sin.” The three conditions are:

Grave matter

Full knowledge (not "and that it is a grave matter)

Deliberate consent

See the CCC article 8 starting at paragraph 1846 for a discussion of sin and of what constitutes a mortal sin. You’ll note full knowledge is qualified by paragraph 1859 which states,

Mortal sin requires full knowledge and complete consent. It presupposes knowledge of the sinful character of the act, of its opposition to God’s law. It also implies a consent sufficiently deliberate to be a personal choice. Feigned ignorance and hardness of heart do not diminish, but rather increase, the voluntary character of a sin.

and paragraph 1860,

But no one is deemed to be ignorant of the principles of the moral law, which are written in the conscience of every man. The promptings of feelings and passions can also diminish the voluntary and free character of the offense, as can external pressures or pathological disorders. Sin committed through malice, by deliberate choice of evil, is the gravest.

Sorry, but this is incorrect. A person isn’t afforded a “free sin pass” just by saying “I wonder if this is a mortal sin.” The three conditions are:

Grave matter

Full knowledge (not "and that it is a grave matter)

Deliberate consent

See the CCC article 8 starting at paragraph 1846 for a discussion of sin and of what constitutes a mortal sin. You’ll note full knowledge is qualified by paragraph 1859 which states,

Mortal sin requires full knowledge and complete consent. It presupposes knowledge of the sinful character of the act, of its opposition to God’s law. It also implies a consent sufficiently deliberate to be a personal choice. Feigned ignorance and hardness of heart do not diminish, but rather increase, the voluntary character of a sin.

and paragraph 1860,

But no one is deemed to be ignorant of the principles of the moral law, which are written in the conscience of every man. The promptings of feelings and passions can also diminish the voluntary and free character of the offense, as can external pressures or pathological disorders. Sin committed through malice, by deliberate choice of evil, is the gravest.

I do apologize for the confusion. I was not saying one can do whatever he or she wants by claiming ignorance. And when I added the ‘knowledge that it is mortal’ it was to have the individual better understand what Full Knowledge actually is. Having full knowledge would also contain within it that the action would be grave or if you think to yourself “Gee this may be a mortal sin but I’m not sure so, lets just commit it anyways” than one may have committed a mortal sin by not caring if they sever their relationship with God even if the act would have just been a venial sin in the first place. Unless that is an incorrect statement maybe you could explain to me better what full knowledge actually is then. An act such as murder which goes against ones internal conscious is of coarse mortal even if the person doesn’t want to recognize it. But lets take masturbation for instance. It is a mortal sin to masturbate however; to someone who has absolutely no knowledge that it is a gravely disordered action their accountability may be less than someone who knows better. I was not saying one gets a “get out of jail free card” by simply being ignorant.